1. Field of the Invention
The invention pertains to the field of sound producing earplugs. More particularly, the invention pertains to eartips for sound producing earplugs.
2. Description of Related Art
Eartips are typically attached to sound producing earpieces to form in-ear earphones or “ear buds”. Earpieces may be custom-made, to form fit to an individual user, or universally-fitting. Eartips are typically constructed out of foam materials, or elastomers such as silicone, in various shapes. The eartip generally creates an acoustic seal with the canal walls which prevents undesirable noise from being heard by the user.
For illustrative purposes, FIG. 1A shows a simple eartip in the form of a foam cylinder 1 with a rubber sound tube 2 glued internally to carry the sound into the ear from an earpiece into the ear.
FIG. 1B is a cross-section of a contoured foam eartip having a tapered cylindrical resilient body 3 with a rubber sound tube 2. One such foam design is shown in US published application No. 2007/0240931 by Killion.
FIG. 1C is a cross-section of a flanged elastomeric tip having a body 4 with flanges 5, usually made from a silicone material. The flanges 5, made of elastomeric material, serve to seal the tip to the ear canal, while the channel 6 in the center serves to couple sound from a speaker in an earpiece to the human ear canal.
FIG. 1D illustrates a foam eartip 7 installed on a custom-molded earpiece 8. The custom earpiece 8 is typically made from an impression of the user for which the device is made. Eartips may also be installed on universally-fitting earpieces.
The effectiveness of any plug at keeping out undesirable outside sounds is determined partially by the depth in the ear canal to which the device is inserted. Deeper insertion generally yields greater attenuation of the undesirable outside sounds. Attenuating outside sounds permits reducing the sound levels required in the ear canal to create a comfortable and useful listening level for communications signals (such as music or speech). Moreover, in loud environments, higher noise attenuation can prevent hearing loss. Additionally, the less air volume there is inside the ear canal to be driven by the speaker in the earpiece, the less energy is required in the system which results in smaller and lighter energy sources, and longer operating life per charge or battery replacement. Finally, deeper insertion reduces the occlusion effect, wherein the wearer's own voice seems to “boom” and be artificially loud while wearing the plugs. It is very desirable, therefore, to place these eartips deeply in the ear canal.
The primary impediment to placing eartips deeply in the ear canal has been the problem of removing them. If they are installed on an earpiece which places them deeply in the canal, then it is possible when removing the earpiece from the ear for the eartip to detach and remain deep in the canal. In this case, medical assistance may be needed to remove the eartip from the canal. The potential for this failure mode can discourage manufacturers from deploying solutions that take advantage of deep placement regardless of the many advantages of doing so.